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ALL ABOUT DOLPHINS
ALL ABOUT DOLPHINS
HOW MANY SPECIES OF DOLPHINS DO YOU THINK THERE ARE?
TAKE A GUESS!Remember: The number of any species of animals can always change if new species are discovered!
THE LARGEST DOLPHIN
THE SMALLEST DOLPHIN
THE MEASUREMENTSOrca/Killer whales:
20-26 feet or 6-8 metersUp to 6 tons or 5443 kilograms
Maui’s Dolphins4-6 feet or 1.2-1.8 meters
95-115 pounds or 43-52 kilograms
HERE ARE JUST A FEW OF THE 44 SPECIES OF DOLPHINS
Risso’s Dolphin PC: Tracie Sugo
Common Dolphin Pink River DolphinPC: Tracie Sugo
ARE DOLPHINS FISH OR MAMMALS?
What do you think?
What are some reasons that you think dolphins are
classified as fish or mammals?
WHAT ARE SOME CHARACTERISTICS OF ALL MAMMALS?
What makes mammals different from fish, amphibians, reptiles and birds?
SOME CHARACTERISTICS OF MAMMALS
● VIVIPAROUS, mammals give birth to LIVE young - they don’t lay eggs!
● NURSE THEIR YOUNG WITH MILK, all mammals provide their young with highly
nutritious milk as they are growing
● WARM-BLOODED, mammals are able to generate their heat internally to maintain
homeostasis - keeping a stable internal environment
● LUNGS TO BREATHE AIR, all mammals breathe air by bringing air into their lungs and
extracting oxygen from that air
● FOUR-CHAMBERED HEART, all mammals have a four-chambered heart that allows
for efficient circulation by separating oxygenated and non-oxygenated blood
ANOTHER CHARACTERISTIC OF MAMMALS
Mammals have HAIR!
Hair provides a way to maintain
heat and stay warm.
DOLPHINS ARE MAMMALS!● Dolphins give birth to LIVE young, they do NOT lay eggs.
● Dolphins nurse their young with milk from the female’s mammary glands
● Dolphins are warm-blooded
● Dolphins have lungs to breathe air
● Dolphins are all vertebrates
● Dolphins have hair on their on their upper jaw at birth but it drops off
about 2 weeks after birth
WHY DO YOU THINK A DOLPHIN’S HAIR DROPS OFF SHORTLY AFTER BIRTH?
Hint: What is the function of hair/fur for mammals?
What do dolphins have for this function that other mammals do not?
Some dolphins such as belugas and narwhals live in the coldest areas on Earth, if they don’t have hair/fur, how do they stay warm?
DOLPHINS HAVE BLUBBER!
Blubber is a thick layer of fat tissue
Fat tissue acts as an insulator
An insulator keeps heat in - houses have insulation in the walls to help keep heat inside the house
Having blubber allowed dolphins to evolve to be hairless as adults - why do you think dolphins might be at a disadvantage if they did have hair/fur for insulation?
Dolphins live in an aquatic world and rely on being fast swimmers both to CATCH their prey
and to AVOID being caught by predators
● Hair adds additional drag when moving through the water
● Drag is a type of resistance that slows down a moving object
● Competitive human swimmers often shave the hair off their entire bodies to
reduce drag
● Not having hair allows dolphins to swim FASTER!
Swimming dolphins: can you imagine how hair would slow them down? (Video)
IF HAVING HAIR IS A DISADVANTAGE FOR DOLPHINS, WHY DO THEY HAVE IT AT ALL?
● Why do YOU think dolphins have hair when they are born, only to
have it drop off at about two weeks after their birth.
● Why aren’t dolphins just born hairless?
The ontogeny of a species can give us clues to its evolutionary history
● Ontogeny = the development of an organism from inception to maturity;
how an organism develops from the moment it is conceived until it is a
mature adult
● Phylogeny = the history of the evolution of a species or group
● HOW MIGHT THIS APPLY TO DOLPHINS?
● Think about the fact that dolphins have hair when they are born
● What type of animal do you think dolphins evolved from? Fish or Mammal?
Why?
WHAT DO YOU THINK THE ANCESTORS OF MODERN DOLPHINS LOOKED LIKE?
● Scientists believe that dolphins evolved from land mammals that returned to the
sea
● Their ancestors are believed to have been similar to small deer
● Those land animals would have had hair/fur
● Fossil evidence documents the transition from land to water
● Dolphins closest living relatives are thought to be hippos
● What other changes in dolphin anatomy have allowed dolphins to adapt to a
completely aquatic life?
DOLPHIN PHYLOGENY
HOW DO DOLPHINS BREATHE?
Dolphins don’t have gills like fish do to extract oxygen from water.
Remember, dolphins are MAMMALS and use lungs to breathe in air. Oxygen is then taken from that air and enters the bloodstream where it is distributed throughout the body.
Dolphins have LUNGS and extract oxygen from the air that they breathe in.
WHERE IS A DOLPHIN’S NOSE?
DOLPHIN BLOWING AIR OUT OF ITS “NOSE”!
A DOLPHIN’S NOSE IS IT’S BLOWHOLE!● Have you ever seen a dolphin breathing? It surfaces, opens its blowhole,
expels air that can be seen as water vapor and takes in a new breath.
● The blowhole has migrated over millions of years of evolution to the top of the
head, making it easy to breathe at the surface of the water.
● The blowhole has muscles which the dolphin controls. It must learn to time it
just right so that the blowhole is open above the water and closes before going
back underwater.
● Newly born dolphin calves can be seen learning to get their swimming and
breathing pattern just right.
DOLPHIN BREATH
How do dolphins sleep?● Dolphins are conscious breathers, meaning they have to think about
breathing
● They must open their blowhole when at the surface and close it before
diving back underwater
IF THEY HAVE TO THINK ABOUT BREATHING, HOW CAN THEY EVER SLEEP?
ANY IDEAS?
● Dolphins are able to sleep by resting one half of their
brain at a time
● Dolphins must be able to come to the surface to
breathe and to be alert in case of danger
● Dolphins sleep with one eye open at all times
● Sleeping dolphins are usually in small groups
● The dolphins swim slowly when they are “sleeping”
WHAT SEPARATES BALEEN WHALES FROM DOLPHINS?
● Baleen whales are the large whales such as humpback whales, blue
whales and others.
● How are dolphins different from these whales?
● What structures do dolphins have that these whales do not?
● What behaviors are different between baleen whales and dolphins?
● What are the social groups for baleen whales and dolphins?
INSIDE A HUMPBACK WHALE’S MOUTH
INSIDE A BOTTLENOSE DOLPHIN’S MOUTH
BALEEN WHALES HAVE A DOUBLE BLOWHOLE
DOLPHINS HAVE A SINGLE BLOWHOLE
ALL DOLPHINS ARE WHALES BUT NOT ALL WHALES ARE DOLPHINS
● Dolphins are toothed whales. They have teeth and baleen whales do not. Baleen
whales have baleen which are large bristle-like structures used in feeding.
● Dolphins have teeth although they use their teeth differently than we do. Dolphins
use their teeth to grasp and immobilize fish and other prey. They swallow their prey
whole. They do not chew their food like we do.
● Dolphins tend to live in social groups called “pods” while baleen whales are usually
solitary animals, sometimes coming together to feed or breed.
DOLPHIN SOCIAL GROUP = PODCOMMON DOLPHIN POD IN MONTEREY, CA (VIDEO)
SOME SPECIES TRAVEL IN SMALLER PODS (VIDEO)
DOLPHIN PODS: GROUPS OF DOLPHINSPod structures include:
● NURSERY PODS: groups of mothers with calves, sometimes accompanied by a few
males, and also with elders whom they protect
● JUVENILE PODS: groups of young adults
● MALE PODS: usually small groups of males that travel together and work cooperatively
● The larger, baleen whales are usually solitary animals that come together to feed and mate while dolphins live in pods.
● What advantages do you think there are for dolphins to form pods? How does being in a group help the dolphins?
WHY DO DOLPHINS FORM PODS?
● Cooperative hunting: working together leads to more successful hunts
● Mating: some dolphins mate within their pod but never with relatives, this occurs in species with large pods; in smaller pods, males will leave the pod to mate and then return to their family pod
● Protection: dolphins are smaller than the baleen whales, there is safety in numbers
ADVANTAGES TO LIFE IN A POD
● Dolphins play together
● Dolphins teach their offspring their pod’s culture including hunting methods
and more
● Many species “alloparent” which means taking care of a calf that is not your
own, like baby-sitting
● Dolphins have exhibited empathy, cooperation and altruism
BIGGEST ADVANTAGE IS SOCIALIZATION
Empathy is the ability to sense others emotions
● Dolphins have been observed grieving over the loss of calf, not just the mother but all pod members
Cooperation is working together for the same end
● Dolphins often work together when hunting
Altruism is selfless concern for others
● Dolphins have been observed helping both their own species and other species with no benefit for the dolphins
DOLPHIN BEHAVIORS THAT MAY INDICATE INTELLIGENCE
● Dolphins are able to communicate with each other by using a series of clicks,
whistles and squeaks. They often work cooperatively when hunting.
● Dolphins are creative and playful. Dolphins have been observed surfing in
waves and creating rings of bubbles as well as other creative play.
● Dolphins pass learning to their offspring. Young dolphins learn how to hunt as
well as other behaviors from their mothers and other podmates.
● Dolphins show emotions, they display sadness and joy.
● There are several populations of dolphins that have been observed using tools.
SIGNATURE WHISTLES
● Shortly after birth, a dolphin will create its own, personal “signature whistle” which is a unique pattern of clicks and whistles that identify it, similar to our “names.”
● Dolphins identify themselves and others by using these signature whistles.● Recent studies show that a dolphin can remember other dolphins’ signature
whistles for up to 20 years!
DANGERS TO DOLPHINS
What do you think a dolphin’s NATURAL predators are? (two)Hint: What is the largest dolphin?
SHARKS FEED ON SMALLER DOLPHINS
ORCAS/KILLER WHALES FEED ON DOLPHINS OF ALL SIZES
HOW DO DOLPHINS INTERACT WITH HUMANS IN THE OCEAN?
How do you think that dolphins interact with humans in the ocean?
Do you think they are scared of us? Friendly? Cooperate with us? Help us?
DOLPHIN LIFE
● Dolphins live in family groups with very tight bonds. They socialize, play, and hunt together. Dolphins can travel 40 miles per day and the larger dolphins, orcas can travel 100 miles a day.
● What do you think life is like for a dolphin that is kept in captivity? Do you think that humans are a danger to dolphins? Why or why not?
RESOURCES AND CREDITSPHOTOS:
“Blue Fish” https://clipartpng.com/?426,blue-fish-png-clipart CC4.0 license
“Dolphin Phylogeny” http://www.dolphin-way.com/dolphins-–-the-facts/evolution/#axzz5MiCURVsM CC4.0 license
“Frog” https://animals.howstuffworks.com/amphibians/frog.htm CC4.0 license
“Humpback Whale Baleen” http://www.australiangeographic.com.au/news/2017/08/not-so-nice-new-study-finds-baleen-wh
ales-were-once-biters CC4.0 license
“Mammal Collage” http://www.ncmountainland.net/nature-gallery/ CC4.0 license
“Maui Dolphin” https://www.flickr.com/photos/earthraceconservation/9258488160 CC4.0 license
“Beluga whale” https://commons.wikimedia.org/wiki/File:Beluga_1_1999-07-03.jpg CC4.0 license
“Pink dolphin” https://www.flickr.com/photos/31830413@N06/2977317822 CC4.0 license
Video Credits:“Sleeping Dolphins from Disney’s ‘Dolphin Reef’
https://www.youtube.com/watch?v=ZLZOnqxa99c
“Dolphins Create Sponge Armor” https://www.youtube.com/watch?v=-zdzROgOELM
“Pilot Whales Grieve Dead Calf” https://www.youtube.com/watch?v=0a8HGJid-Jo&frags=pl%2Cwn
“Dolphins Help Fishermen” https://www.youtube.com/watch?v=-THGIPMkM3s&frags=pl%2Cwn
“Dolphins Help Lost Baby Seal” https://www.youtube.com/watch?time_continue=12&v=fB3FT3t6_sE&feature=emb_title
“How Dolphins Respond to ‘Name’ Whistles”https://www.youtube.com/watch?v=zAjHtYh5Amo
“Dolphins Protect Diver from Shark” https://www.youtube.com/watch?v=T3pXhU5vzas&frags=pl%2Cwn
“Dolphins Work Together to Catch Fish” https://www.youtube.com/watch?v=-THGIPMkM3s&frags=pl%2Cwn
ALL OTHER PHOTOS AND VIDEOS USED WITH PERMISSION FROM:
Dolphin Project Cynthia Fernandez
Kate Cummings Tracie Sugo
